Lift bridge



1929- G. H. ALLEN ET AL LIFT BRIDGE Filed Sept. 6; 1927 4 Sheets-Sheet AI m e22 500%; d. M

ATTORNEYS.

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' ATTORNEYS.

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M152? BY y 'Zen'n #14 [Z 728271 06 Patented Oct. 15, 1929 UNITED STATES PATENT orrles GLENN I-I. ALLEN AND THURLOE M. HAGENBOOK, OF EVANSVILLE, INDIANA, AS SIGNORS TO THE INTERNATIONAL STEEL AND IRON COMPANY, OF EVANSVILLE, INDIANA, A CORPORATION OF INDIANA I I LIFT BRIDGE Application filed. September 6, 1927. Serial No. 217,768.

Our invention relates to lift bridges and more particularly to a system for accurately balancing lift bridge structures for enabling such structures to be readily operated with minimum motive power.

One of the objects of our invention is to provide a construction of lift bridge having means for accurately balancing the lift bridge after installation to meet a wide variety of operating conditions and to enable the bridge to be accurately balanced for movement to selected positions with the expenditure of minimum effort.

Another object of our invention is to pro- Vide a construction of counter-weight for a lift bridge structure wherein the center of gravity of the counter-weight and bridge structure may be shifted to a selected position for accurately balancing the lift bridge and permitting movement thereof in balanced condition to or from a substantially horizontal normal position to an angular position removed from the normal position.

Still another object of our invention is to provide a bascule bridge construction having a system of counter-weights each arranged for variation in the mass'thereof for shifting and selectively fixing the center of gravity of the counter-weight and bridgestructure' for accurately balancing the bridge structure.

Another object of our invention is to pro vide a construction of counter weight for a bascule bridge, in which a plurality of counter-weights are provided each having pockets formed therein distributed through the counter-weight on opposite sides of a line passing through the normal center of gravity of the counter-weight and the bascule bridge structure, ceive removable sections of ballast for enabling the center of gravity of the bridge structure to be shifted tothat degree necessary to accurately balance the bridge struc ture and permit movement of the bridge structure around a pivot with the expenditure of minimum effort.

Still another object of our invention resides in the arrangement of counter weights having removable sections therein and operating mechanism for shifting the position 'terw ays the pockets being arranged to re of the bridge under control of the counterweights where the operating mechanism is capable of being longitudinally moved with minimum effort for shifting the entire bridge structure from a substantially horizontal position to an elevated position.

Our invention will be more clearly understood from the specification hereinafter following by reference to the accompanying drawings wherein: 1

Figure 1 is a side elevation of a bascule bridge structure embodying the counterweight system and operating mechanism of ourinvention; Fig. 2 is a plan view showing the bridge structure and counter-weight system carried thereby in accordance with our invention; Fig. 3 is an end view partially in cross-section showing the operating mechanism of the bascule bridge structure and the arrangement of counter-weights on the bridge structure; Fig. a is an enlarged view showing the arrangement of the operating mechanism; Fig. 5is a cross-sectional view taken on line 5 5 of Fig. 4 showing the manual actuator for elevating or lowering the bridge; Fig. 6 is a longitudinally crosssectional view taken through one of the counter-weights employed in the bridge structure of our invention;'Fig. 7 is a cross-sectional view taken on line 77 of Fig. 6; and Fig. 8 is a lateral cross-sectional view taken through the counter-weight on line 88 of Fig. 6.

In the construction of bascule bridges where rivers streams, canals and other waare to be spanned and arrangements made to swing the bridge to a vertical position for clearance and passage of a vessel, the balancing of the bascule bridge is extremely important part of the design of the bridge structure. Bascule bridges are often employed at remote places where power is not available and the bridge must be capable of manual movement. The raising of a bascule bridge from a normally horizontal position to a substantially vertical position by manual power is extremely diiiicult unless the bridge has been accurately designed with respect to distribution of mass for the balancing of the bridge about its trunnions. Despite engineer ing care which may be taken in the design of lift bridges, experience in the field has shown that problems, not apparent to the engineer, in originally planning the bridge structure, will arise and usually the balancing of the bridgebecomes a cut and try method of pouring cement into a counter-weight and attempting by the mass of the counter-weight to counter-balance the bridge structure in just that degree necessary for securing an accurate balance. Experience in the field has shown that the pouring of cement in the counter-weight is very likely to be misjudged, and oiten the counter-weight becomes of such mass that the bridge cannot be balanced throughout its range of movement. The result is that it is necessary to chip away the cement from the counter-weight with the hope of obtaining just that mass necessary to efii'ect balance or the bridge- The removal ofthe poured cement from the counter-weight is a tedious and undesirable task and the results accomplished are oftenunreliable and the cut and try methods wasteful or time and energy.

In the bridge construction of our invention we provide a system of counter-weights on opposite sides of one end of the bridge, and through the counter-weights on opposite sides or alin'e which passes through the normal center of gravity of the counter-weight and bridge system, we distribute pockets so disposed in the counter-weights that ballast blocks may be received in positions both above and below the normal center of gravity of the bridge and counter-weight structure. The arrangement of the removable ballast weights in the bridge construction enables the bridge structure to be accurately balanced to such a degree that the bridge may be moved to either of the extreme positions under control of one man: The huge weight of the bridge structure may be so distributedby reasonof the positioning of the ballast blocks in the pockets distributed throughout the counterwei'ght system in the bridge structure of our invention that the inertia of the bridge to be shifted in position may be compensated, and the mechanical system described herein manually controlled for ellecti'ng movement of the bridge structure.

In field experience it has been foundthat the norm'al unbal-anci'ng of a bascu-le bridge may be such that while the brid' 'e may be raised lnaiulally aiter considerable effort, it

is not possible to lower the bridge under the same manual control. In such instances it has been necessary to resort to the expedient of attempting to pullthe bridge down by cables drawn over the end or the bridge. Such conditions as these are entirely overcome in the bridge structure and couirteruveight system of our invention, where removable ballast may be added to or subtracted from the mass of the counter-weight on opposite sides of a line norm-ally passing through the Gen- ,21 of the bridge structure 2. The counterweights 5 comprise box-like frame structures bounded by segmental end pertions 26, the side walls 27 and 28v of the counter-weights being bound together by tie rods 29 provided with suitable spacer members 3G, thecountei weights having two walls thereof disposed substantially at right angles, while the top wall thereof forms an obtuse angle with respect to one of the end Walls, the; segmental wall 26 closing the counter-weight, thereby providing a box-like structure for receiving the cement ballast represented generally at 31. A cable 9 is attached to one end of the counter-weight at 10 and extends over the segmental shaped w'all26to the talresup drum 7 which is carried by shaft 6. Cable 8 is at tachcd at 11 to the opposite end of the counter-weight and is wrapped'upon the take-up drum 7 in such man-nerthat as the top cable 9 winds around the drum the bridge risesand the bottom cable 8 unwinds from the drum. The reverse is true when the bridge is lowered. Cement may be poured into the boxlike structure of the counter-weightuntil it assumes a position represented by dottedline 12. The walls of the counter-weight may be built up and extended upon the frame structure to the full height of the segmental truss should it become desirable.

Throughout the co unteruveight we provide pockets represented at 15-161718-19 which may be opened from one side of the counter-weight by the removal of side plate n'iem-bers 15, 16, 1-7, 18 and 19*. Each of the pockets l51 6-17-18-19 extend from one side wall of the counter-weight to the opposite wall and provide braces for the walls of the counter-weight at the same time that space is provided to receive ballast blocks which We have represented generally at 32,

V The ballast blocks 32 are formed of such a size as will accommodate a multiplicity of rows of the ballast blocks. Upon the insertion of the required number of ballast blocks bracing means represented at 33 be provided for securing the ballastblocks inposition regardless of the angular movement of the bridge structure. The box-like pockets distributed throughout the counter-weight each have a row of retaining bolts represented at 34: projecting therefrom upon which the plate members may be secured for closing the pockets, the bolt members being anchored in the cement which fills in between the pockets during the normal filling of the counterweight during the pouring operation. It will be observed that the pockets are distributed on opposite sides of a line 14 which passes through the trunnions of the bridge and through the normal center of gravity of the bridge structure and counter-wei ht system. This permits a shifting of the center of gravity of the bridge structure and counter-weight to a position above or below normal in accordance with the requirements of balancing the bridge structure.

The ability to manually elevate and lower the bridge structure depends largely upon the accuracy in the balancing of the bridge structure. The shaft 6 which carries the drums 7 is located in a pit 23 below the approach 24 of the bridge by means of a system of gears represented at 35 as enclosed within housing 20 from which projects the operating device 46. The main gear 36 is carried by shaft 6 and meshes with a smaller gear 37 which is keyed to another shaft 38. The shaft 38 carries the worm gear 39 in housing 40. A co-acting worm wheel 41 meshes with the vorm gear 89 and may be moved by means of the operating device 46. Under conditions of accurate balancing a small force imparted to the operating device 46 may be multiplied to shift the position of the bridge to the desired position with a small expenditure of manual effort. The housing 20 may be suit- I ably enclosed to protect the gearing with merely the operating device 46 projecting therefrom. By reason of the inherent selflocking construction of the worm wheels 39 and 41 the bridge when once moved to a selected position will remain in that position. An accurate balancing of the bridge over its entire range of movement may be secured by the shifting of the ballast blocks 32 to desired positions in the pocket within the area of the counter-weight thereby distributing the weight on either side of a line passing through the trunnions and the center of gravity of the counter-weight and bridge. In order to increase the rigidity of the bridge structure and counter-weight system, we provide a suitable truss structure 42 forming a tie between the counter-weights.

T ie bridge constructed herein has proven to be highly practical. for fabrication and successful. in its use, and while we have described a particular embodiment of our invention, we desire that it be understood that modifications may be made and that no limitations upon our invention are intended other than are imposed by the scope of the appended claims.

lVhat we claim as new and desire to secure by Letters Patent of the United States is as follows:

1. In a lift bridge a ballast portion, a bridge portion, trunnions between said portions, said posite side wall thereof, said pockets being disposed on opposite sides of a line passing through the center of gravity of said bridge, and being arranged to receive independent ballast blocks between the side walls of said counter-weight for selectively distributing the weight of the poured mass in predetermined manner throughout the counter-weights and cables extending over the segmental peripheries of said counter-weights for moving saidweights in different positions about the trunnions of said bridge.

2. In a lift bridge structure, a ballast portion, a bridge portion, trunnions between said aortions, said ballast portion comprising a pair of counter-weights on opposite sides of one end of the lift bridge structure, each of said counter-weights comprising box-like enclosures for receiving a mass of material, said box-like enclosures having a substantially seg- 'm.ental shaped periphery, said box-like enclosures being apertured throughout a plurali ty of portions of the area thereof and on opposite sides of a line passing through said trunnions and the center of gravity of said counter-weights and bridge, for forming pockets extending between one side wall of the box-like enclosures and the opposite side wall thereof for receiving individual ballast blocks between the side walls of said counterweights for distributing the mass of the counter-weight in predetermined manner through outthe area thereof, and cables extending over the segmental peripheries of said counterweights for moving said weights in different positions about the trunnions of said bridge.

3. In a lift bridge structure a ballast portion, a bridge portion, trunnions between said portions, said ballast portion including a counter-weight comprising a box-like enclosure for receiving a poured mass of material, said enclosure having a substantially segmental shaped periphery and a plurality of pockets distributed about said counter-weight in positions on opposite sides of a line passing through the normal center of gravity of the counter-weight and bridge structure, said pockets extending throughout the area between the side walls of said counterweight being arranged to receive individual ballast blocks for distributing the mass of thecounter-weight in predetermined manner and cables extending over the segmental peripheries of said counter-weights for moving said weights in different positions about the trunnions of said bridge.

4. In a lift bridge structure a ballast portion, a bridge portion, trunnions between said portions, said ballast portion including a countenweight, said counter-Weight com prising a boXlike frame arranged to receive a poured mass of material, said frame having a substantially segmental shaped periphery and aplurality of pockets formed in said box-like frame and extending between one side Wall of said box-like frame and the other side Wall thereof, and each closed by a removable plate extending over one side wall of the box-like frame, said pockets being arranged on opposite sides of a line passing through said trunnions and the center of gravity of said counter-Weight and bridge and arranged to receive a plurality of individual ballast blocks for distributing the mass of the counter-Weight in predetermined manner and a cable extending over the segmental sha-ped counter-Weight for moving said Weight in different positions about the trunnions of said bridge.-

5. In a lift bridge striaicture a cantilever bridge pivotally mounted on trunnions adjacent one end thereof, a counter-Weight in the plane of each truss of the bridge for balancing said. cantilever bridge, each of said counter-Weights comprising asubstantially segmental shaped housing having a plurality of cells therein disposed on opposite sides of a line passing through the normal center of gravity of said counter-Weight an'd cantilever bridge and through the trunnions, each of said cells being arranged to receive individual ballast blocks between the side Walls of the counter-weights for shifting the center of gravity of said counter-Weight to that degree necessary to balance said bridge for movement about said trunnions and cables extending in surface contact with the segmental counter-Weights for moving said Weights in ditl'erent positions about the trunnions of said bridge.

In testimony whereof We afiix our signatures.

GLENN H. ALLEN. THURLOE M. HAGENBQOK. 

